Printed Stretchable Conductors for Smart Clothing: the Effect of Conductor Geometry and Substrate Properties on Electromechanical Behaviors

Smart clothing is where the capability of sensing, responding, and adapting to environmental stimuli such as electrical, mechanical, chemical, and thermal is embedded into textiles to ensure functional, fashionable, and comfortable solutions to everyday human needs. Hence, it is an ideal avenue to bring wearable technology closer to human beings and enable easy access to Internet of Things (IoT). Integration of electronic functionality to textiles is essential to realize the true potential of many smart clothing applications. Further, the ability of such electronics systems to stretch, without significant deterioration in electrical properties, is a key performance requirement in many of the smart clothing applications. The electromechanical reliability of conductors under tensile strains is influenced by the conductor geometry and the properties of the substrate. The objective of the present work is to understand the collective effect of print orientation, width, and thickness on the electromechanical behaviors of meandering conductors printed on an anisotropic, stretchable textile substrate. Meandering conductors with distinct features were fabricated on a knitted fabric substrate with a commercially available stretchable silver conductive ink. Printed conductors were optically and electrically characterized under loaded and unloaded conditions. Statistical analysis revealed that the print orientation, width, and thickness of the printed conductors could significantly affect their electromechanical performance.